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1.
Phys Rev Lett ; 133(12): 121004, 2024 Sep 20.
Article in English | MEDLINE | ID: mdl-39373410

ABSTRACT

We report results from an analysis aimed at detecting the trispectrum of the kinematic Sunyaev-Zel'dovich (kSZ) effect by combining data from the South Pole Telescope (SPT) and Herschel-SPIRE experiments over a 100 deg^{2} field. The SPT observations combine data from the previous and current surveys, namely SPTpol and SPT-3G, to achieve depths of 4.5, 3, and 16 µK-arcmin in bands centered at 95, 150, and 220 GHz. For SPIRE, we include data from the 600 and 857 GHz bands. We reconstruct the velocity-induced large-scale correlation of the small-scale kSZ signal with a quadratic estimator that uses two cosmic microwave background (CMB) temperature maps, constructed by optimally combining data from all the frequency bands. We reject the null hypothesis of a zero trispectrum at 10.3σ level. However, the measured trispectrum contains contributions from both the kSZ and other undesired components, such as CMB lensing and astrophysical foregrounds, with kSZ being sub-dominant. We use the agora simulations to estimate the expected signal from CMB lensing and astrophysical foregrounds. After accounting for the contributions from CMB lensing and foreground signals, we do not detect an excess kSZ-only trispectrum and use this nondetection to set constraints on reionization. By applying a prior based on observations of the Gunn-Peterson trough, we obtain an upper limit on the duration of reionization of Δz_{re,50}<4.5 (95% confidence level). We find these constraints are fairly robust to foregrounds assumptions. This trispectrum measurement is independent of, but consistent with, Planck's optical depth measurement. This result is the first constraint on the epoch of reionization using the non-Gaussian nature of the kSZ signal.

2.
Appl Opt ; 59(10): 3285-3295, 2020 Apr 01.
Article in English | MEDLINE | ID: mdl-32400613

ABSTRACT

We present two prescriptions for broadband ($ {\sim} 77 - 252\;{\rm GHz} $), millimeter-wave antireflection coatings for cryogenic, sintered polycrystalline aluminum oxide optics: one for large-format (700 mm diameter) planar and plano-convex elements, the other for densely packed arrays of quasi-optical elements-in our case, 5 mm diameter half-spheres (called "lenslets"). The coatings comprise three layers of commercially available, polytetrafluoroethylene-based, dielectric sheet material. The lenslet coating is molded to fit the 150 mm diameter arrays directly, while the large-diameter lenses are coated using a tiled approach. We review the fabrication processes for both prescriptions, then discuss laboratory measurements of their transmittance and reflectance. In addition, we present the inferred refractive indices and loss tangents for the coating materials and the aluminum oxide substrate. We find that at 150 GHz and 300 K the large-format coating sample achieves $ (97 \pm 2)\% $ transmittance, and the lenslet coating sample achieves $ (94 \pm 3)\% $ transmittance.

3.
Mol Pharm ; 9(10): 2924-32, 2012 Oct 01.
Article in English | MEDLINE | ID: mdl-22905779

ABSTRACT

The use of hot-melt extrusion for preparing homogeneous API-excipient mixtures is studied for miconazole-PEG-g-PVA [poly(ethylene glycol)-poly(vinyl alcohol) graft copolymer] solid dispersions with a 5 cm(3) table-top, twin-screw corotating microcompounder (DSM Xplore). Phase behavior of PEG-g-PVA, miscibility of miconazole in PEG-g-PVA and the partitioning of miconazole between PEG and PVA amorphous phases are characterized using a combination of modulated DSC, XRPD, and solid-state (1)H and (13)C NMR methods. The (1)H NMR transverse magnetization relaxation (T(2) relaxation) method is used to analyze the phase composition and molecular mobility of the copolymer. The T(2) relaxation decay of pure PEG-g-PVA can be described by four T(2) relaxation components in the temperature range studied. PVA crystallinity is not largely affected by hot-melt extrusion and the presence of the drug. Miconazole preferably resides in the PEG amorphous phase, and its molecules are well dispersed in the PEG-g-PVA matrix using hot-melt extrusion mixing. Miconazole forms amorphous nanoclusters whose average size equals approximately 1.6 nm, indicating solid solution formation (molecular level dispersion) of the drug in the polymer.


Subject(s)
Excipients/chemistry , Miconazole/chemistry , Polyethylene Glycols/chemistry , Polyvinyl Alcohol/chemistry , Chemistry, Pharmaceutical/methods , Drug Carriers/chemistry , Hot Temperature , Nanoparticles/chemistry , Particle Size , Solubility
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